Topic: Black Rubber Pucks under cam towers...?

[chaloots]

First time rebuilding CB750K8 engine.  Just finished removing Rocker Assembly, Cam and Camtowers.  All head fasteners removed except the six under the Black Rubber Pucks.

How do you remove the pucks?  Don't want to booger up the head.

Pucks seem to be stiff, not very rubber-like.  They are flush with the head surface and
I don't want to pry them up and damage the head.  I pushed on one and it broke away and popped down and into the head below!

Here's a shot of the head... (if the pic posts, it didn't in preview mode!)

[markb]

You are going to remove the head anyway so don't worry about the one that popped through.  They are rubber and they should come out easy.  Don't worry about trying to save them.  You have to replace them anyway.  I hate to tell you this now but the screws under the pucks should be removed first.  Once the head nuts are removed there is a lot more pressure on the remaining screws and makes them harder to remove.
Mark

[Gordon]

I hate to tell you this now but the screws under the pucks should be removed first.  Once the head nuts are removed there is a lot more pressure on the remaining screws and makes them harder to remove.
Mark

You could also warp the head by not loosening the head nuts in the correct order. 

[KRONUS0100]

plus one on the removal order.  but if you are anal retentive detail oriented like me and some others.....some very fine pointed picks like those from harbor freight will remove the pucks without damage to head.

[chaloots]

Thanks for the imput everyone.  Didn't realize that in disassembly,and hopr that nuts/bolts needed to be un-torqued in sequence.  At this point, will get the puck out   and attempt to break away the six screws, carefully... and hope that there is no head warp.

Thanks again for the help.

[markb]

You might want to consider putting the head nuts back on (in the right order) and retorque them before you try to remove the screws.  How I learned this lesson a long time ago is I broke one of them trying to get them out.  As far as removing the pucks, seems like if you have fingernails you should be able to pick them right out.  By the way, I'm not sure on the K8's but on earlier engines there's six pucks but only four screws.

[Duke McDukiedook]

Thanks for the imput everyone.  Didn't realize that in disassembly,and hopr that nuts/bolts needed to be un-torqued in sequence.  At this point, will get the puck out   and attempt to break away the six screws, carefully... and hope that there is no head warp.

Thanks again for the help.

Run, don't walk to the FAQ area of the forum and download the Honda service manual for your bike, it will show the real way to disassemble the bike without screwing things up.

[MCRider]

You might want to consider putting the head nuts back on (in the right order) and retorque them before you try to remove the screws.  How I learned this lesson a long time ago is I broke one of them trying to get them out.  As far as removing the pucks, seems like if you have fingernails you should be able to pick them right out.  By the way, I'm not sure on the K8's but on earlier engines there's six pucks but only four screws.

yes to all this. You don't have to torque the head nuts all the way down, give them 2/3 or so. Keep them in sequence per the manual. But I HIGHLY recommend putting the head nuts back on before attempting to remove the 4 6mm bolts hiding beneath 4 of the rubber pucks.

[chaloots]

>Good suggestion... will put the head nuts back on torque them in proper sequence, then remove all in the proper sequence. 

>I've removed the pucks and they were hard and brittle, like phenolic.  A few were a bit soft in the center and I just poked thru and pulled them out in pieces.
I've got fingernails but needed dental tool to get out.

>Yes, right on...there are six (6) pucks and four (4) screws.

>Downloaded the Honda Service Manual.  Thanks for the tip.

I'll work on this when I get back to the garage tonight.

This is a terrific forum, you guys have so much info to offer up,
and I have so much to learn.  Thanks all.

[MCRider]

You might want to consider putting the head nuts back on (in the right order) and retorque them before you try to remove the screws.  How I learned this lesson a long time ago is I broke one of them trying to get them out.  As far as removing the pucks, seems like if you have fingernails you should be able to pick them right out.  By the way, I'm not sure on the K8's but on earlier engines there's six pucks but only four screws.

yes to all this. You don't have to torque the head nuts all the way down, give them 2/3 or so. Keep them in sequence per the manual. But I HIGHLY recommend putting the head nuts back on before attempting to remove the 4 6mm bolts hiding beneath 4 of the rubber pucks.

Then on the other hand, no reason not to torque them all the way down. You'll be replacing the headgasket anyway.

You can get to the 2 outside bolts thru the cylinder head fins, with a thin 10mm open end wrench. You may be able to get to all 4 from the top with a thin wall socket. And/or they all have phillip heads on them, at times these alone can be used but often they round out and you have to use the hex.

[chaloots]

OK... back in the garage last night after a little break for the Ice Storm here in NNJ.

Put the head nuts back on and torqued them down. Then removed the nuts and screws in the proper sequence.  Pulled the head and... Rust and Muck everywhere.  Jeez, what a mess!  And I had a problem with the little black rubber pucks !!

Take a look at the pics...

          http://s1179.photobucket.com/albums/x391/heychaloots/

I knew the engine was stuck.  The PO said that the bike had been sitting outdoors under a cover (?)
and hadn't hadn't been run in several years. Thought the rings may be tight to the cylinder with some corrosion, and that with a little soak they would break away.   If it didn't loosen up, Ok since I was planning to tear it down anyway.   Didn't expect to find this.  Will try to pull the cylinders away from the pistons, maybe using the gear puller method that I saw on another post in the Tech Forum. Anyway, not too optimistic, not too happy.

So, at this point does it look like it might be a salvageable engine? ... or just another anchorweight!

[TwoTired]

Is the fluid oil?

All I see is loose combustion deposits mixed with a fluid.  Can't see any cylinder wall damage yet.  You need to see the swept area of the cylinder wall to make a prognosis.  Pitting is bad.  Smooth is okay.

[chaloots]

The fluid you see in the cylinders is PB Blaster that I put down the spark plug hole a few weeks ago to let soak... hoping to free things up.  The muck is in the end cylinders only, and is probably 1/2 inch thick and kinda granular-like mixed with the PB Blaster. The exhaust ports of each of those cylinders had a deposit of white dry granular-like stuff (reminded me of battery terminal deposits, although not acidic). So I suspect what's in the cylinders is the same stuff, just wet with PB Blaster.  No idea what the white stuff is.   

[TwoTired]

FYI, cylinder combustion deposits can appear tan, brown, black, and even white.

Aluminum oxide is white, too.  (Pistons and cylinder head decomposition)  Corrosion of steel or iron based materials usually show up reddish.

Did you find the white stuff in the intake runners/ports, too?

It's all fixable.  You just need a closer inspection to determine what has to be replaced or resurfaced.

Cheers,

[chaloots]

The intakes were clean, no white stuff. Two exhaust ports were packed with the stuff into the valve stems and into the headers as well. Aluminum oxide or , man it was a lot of stuff. I was wondering if the engine had spent any time under the sea? (Speaking of anchorweight!)  Although the topside of the head looks good, no oxidation of any kind on any of the valve train components, rockers, springs, fasteners, chain, camshaft etc., everything was clean and well oiled, and the exterior of the entire engine was relatively clean for sitting around for so long.  So it was a surprise to see all the corrosion in the chambers and cylinders.   

Wasn't able to get back into the garage tonite... had to work late. But I'm looking to get everything cleaned up, and get the pistons out of the cylinders ASAP, and go from there.